There was a lot of paper and ink wasted Wednesday morning on stories about Amar’e Stoudemire and his plus-minus when he shared the court with Carmelo Anthony.

Whether or not those two can play together is far from the Knicks’ biggest question right now, and not close to their largest problem. Getting the Melo-Amar’e chemistry right was a real worry when the team was playing great basketball and streaking to the best record in the Eastern Conference.

Their defense is bad — and it has been that way for some time. New York’s prolific offense, ball protection and three-point shooting hid the problem for a bit, but as their shooting clangs back down to earth, the lack of ‘D’ is becoming more and more glaring.

In November, the Knicks were the 10th-best defense in the league, according to points per 100 possessions. In December, the Knicks were ranked 20th.

For those of you who don’t like advanced statistics, opposing teams are scoring 97 points per game against the Knicks, 17th-best in the league. Teams are shooting 46 percent from the field (No. 21 in the league) and 37 percent from behind the arc (No. 23).

Those are terrible numbers.

In recent games, far-from-offensive-powerhouse teams like the Kings, Trail Blazers and Bulls have put up 100 points on the Knicks. New York is unlikely to get out of the second round of the playoffs if the team plays this sort of poor defense. It’s the main reason the Knicks are only 3-5 in their last eight games. They’ve allowed 100 points or more in every one one of those losses, and less than a 100 in each victory.

Part of it is scheme and falls on the head coach. Mike Woodson has always switched too much, and he puts his players in too many mismatches. The Knicks also double-team way too much, but there’s no way to know if that’s the coach’s direction or coming from the players on the floor. There’s also a small personnel problem, with Pablo Prigioni and Jason Kidd unable to guard quick point guards, and Iman Shumpert not yet healthy enough to make his season debut.

A huge majority of the blame falls on the players and their lack of consistent effort over a 48-minute game. A number of times this season we have seen the Knicks come out flat and let teams score at will in the first half or the first three quarters. It has only been after a fiery halftime talk by Woodson, or a decision by the players, that they actually want to put in the defensive effort necessary to win. The Knicks have been a superior fourth-quarter defensive team all year, indicating they can play well on that end of the floor when they want to.

In first halves this year, the Knicks are the 28th-worst defensive team in the league if you go by points per 100 possessions. In the second half, their defense improves to 8th-best in the league. If you dig deeper, the Knicks are the No. 3 defensive team in the entire NBA in the fourth quarter. I somehow doubt Woodson’s defensive schemes change in the fourth quarter. The only explanation is that the Knicks are playing harder. Of course, the implication is that for the other three quarters, the team isn’t putting the effort necessary in on defense.

This could be explained away by random chance or luck if the numbers weren’t so disparate. The Knicks are giving up an average of 51 points per first half this year. In the second half that drops to 46. In the fourth quarter they allow an average of just less than 22 points. Teams only shoot 40 percent on the Knicks in the fourth quarter, No. 4 in the NBA.

The defense gets progressively better as the game goes on, and the difference is significant.

The only explanation is effort, and that is inexcusable. It’s understood that maximum effort can’t be given every minute of every game over an 82-game season, but it isn’t acceptable to give virtually no effort for a half or three quarters.

As the Knicks proved against the Kings and Trail Blazers, fourth-quarter comebacks are tenuous propositions at best. If the Knicks want to be a top-two team in the conference and challenge for a title, this has to change quickly. It is a good sign that the team can play great defense when they have to, and perhaps in the playoffs they will do it for entire games and series, but counting on flipping a switch is dangerous.

Based on his press conferences, and how the Knicks often come out of halftime or timeouts, Woodson is preaching defense. He knows it’s the team’s primary problem and the key to ultimately winning a championship.

It is up to the players to commit on that side of the floor and make it their focus for 48 minutes. That’s the only way it changes and gets better.

Woodson needs to get them to buy in, and it should start with Anthony, who is fading back into many of his bad defensive habits. If the team’s star commits on defense for 48 minutes, everyone else will follow.

If that doesn’t happen this will be another Knicks season that could end in disappointment.

You can follow me on Twitter @Schmeelk for everything Knicks, Giants, Yankees and New York sports.

Your thoughts on the Knicks’ (lack of) ‘D’? Be heard in the comments below…